Method and apparatus for harq-ack transmission in traffic adaptive tdd system

ABSTRACT

A method and an apparatus are provided for HARQ-ACK feedback information transmission in a traffic adaptive TDD system. The method includes receiving, on a physical downlink control channel (PDCCH), downlink control information for scheduling a physical downlink shared channel (PDSCH), wherein the downlink control information includes a resource indicator indicating at least one physical uplink control channel (PUCCH) resource for transmitting the HARQ-ACK information and power control information for controlling transmission power of a UE; determining the transmission power of the UE based on the power control information; and transmitting the HARQ-ACK information based on the at least one PUCCH resource and the determined transmission power.

PRIORITY

This application is a Continuation of U.S. Ser. No. 16/426,686, which was filed in the U.S. Patent and Trademark Office (USPTO) on May 30, 2019, which is a Continuation of U.S. Ser. No. 14/417,294, which was filed in the USPTO on Jan. 26, 2015, issued as U.S. Pat. No. 10,314,016 on Jun. 4, 2019, which is a National Stage application for International Application No. PCT/KR2013/006750, which was filed Jul. 26, 2013, and claims priority to Chinese Patent Application No. 201210262044.2, which was filed in the State Intellectual Property Office on Jul. 26, 2012, the entire content of each of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates generally to radio communication technologies, and more particularly, to a method and an apparatus for transmitting a Hybrid Automatic Repeat reQuest-Acknowledgement (HARQ-ACK) of a Physical Downlink Shared Channel (PDSCH) in a traffic adaptive Time Division Duplexing (TDD) system when a TDD uplink and downlink configuration of a cell dynamically changes with uplink and downlink traffic.

2. Description of the Related Art

Long Term Evolution (LTE) technology supports a Frequency Division Duplexing (FDD) mode and a TDD mode.

FIG. 1 illustrates a frame structure in an LTE TDD system.

In the LTE TDD system, the length of each radio frame is 10 ms, and each radio frame is divided into two 5 ms half frames. Each half frame includes 8 0.5 ms time slots and 3 lms special domains. The 3 special domains include a Downlink Pilot Time Slot (DOTS), a Guard Partition (GP) and an Uplink Pilot Time Slot (UpPTS), and each subframe includes two continuous time slots.

The transmissions in the TDD system include transmissions from a base station to a User Equipment (UE), i.e., downlink transmissions, and transmissions from the UE to the base station, i.e., uplink transmissions. According to the frame structure illustrated in FIG. 1 , the uplink transmission and the downlink transmission in each 10 ms period share 10 subframes, and each subframe is assigned to the uplink transmission or the downlink transmission. The subframe assigned to the uplink transmission is referred to as an uplink subframe, and the subframe assigned to the downlink transmission is referred to as a downlink subframe.

The TDD system supports 7 types of uplink and downlink configurations, as shown in Table 1 below. In Table 1, “D” indicates downlink subframes, “U” indicates uplink subframes, and “S” indicates special subframes including the above-described 3 special domains.

TABLE 1 TDD UL/DL config- switching uration point subframe index index period 0 1 2 3 4 5 6 7 8 9 0  5 ms D S U U U D S U U U 1  5 ms D S U U D D S U U D 2  5 ms D S U D D D S U D D 3 10 ms D S U U U D D D D D 4 10 ms D S U U D D D D D D 5 10 ms D S U D D D D D D D 6 10 ms D S U U U D S U U D

In order to increase the transmission rate of users, a newer version LTE TDD system has been proposed, which has the same HARQ transmission timing as the older LTE TDD system.

Specifically, the HARQ-ACK of PDSCH may be transmitted in a Physical Uplink Shared Channel (PUSCH) and a Physical Uplink Control Channel (PUCCH). For a timing from the PDSCH to the PUCCH, for example, the UE transmits the HARQ-ACK in the PUCCH of uplink subframe n, the PUCCH indicates the PDSCH in downlink subframe n-k and the HARQ-ACK released by Semi-Persistent Scheduling (SPS), where k∈K. The value of K is defined in Table 2 below, and K is a set of M elements, represented as {k₀, k₁, . . . k_(M-1)}. Further, K relates to the serial number of a subframe and TDD uplink and downlink, and is referred to as a downlink association set. An element k is referred to as a downlink association element.

Hereinafter, downlink subframes corresponding to the downlink association set are referred to as a bundling window, i.e., for all k elements in K, the downlink subframes are a set {n-k, k∈K} composed of n-k elements. In a PUCCH subframe, each PDSCH of each downlink subframe is assigned PUCCH resources for transmitting the HARQ-ACK.

TABLE 2 TDD UL/DL configuration subframe n index 0 1 2 3 4 5 6 7 8 9 0 — — 6 — 4 — — 6 — 4 1 — — 7, 6 4 — — — 7, 6 4 — 2 — — 8, 7, 4, 6 — — — — 8, 7, — — 4, 6 3 — — 7, 6, 11 6, 5 5, 4 — — — — — 4 — — 12, 8, 6, 5, — — — — — — 7, 11 4, 7 5 — — 13, 12, — — — — — — — 9, 8, 7, 5, 4, 11, 6 6 — — 7 7 5 — — 7 7 —

With the increasing requirements for data transmission rates, a traffic adaptive TDD technology has been proposed in the newer LTE version. By dynamically adjusting the ratio between uplink subframes and downlink subframes, the current uplink and downlink configuration more accords with the ratio between the current uplink traffic and downlink traffic, thereby improving the uplink and downlink peak rate of users and system throughput.

In the traffic adaptive TDD system, a TDD uplink and downlink configuration followed by the HARQ-ACK timing from the PDSCH to the PUCCH may be different from an actual TDD uplink and downlink configuration. For example, high-layer signaling or physical layer signaling may indicate a reference TDD uplink and downlink configuration, and whatever the actual TDD uplink and downlink configuration is, the HARQ-ACK of the PDSCH is transmitted according to the HARQ-ACK timing corresponding to the reference TDD uplink and downlink configuration indicated by the high-layer signaling or the physical layer signaling. For example, if the indicated reference TDD uplink and downlink configuration is TDD uplink and downlink configuration 2 and the actual TDD uplink and downlink configuration is TDD uplink and downlink configuration 0, 1, or 6, because downlink subframes of the actual TDD uplink and downlink configuration are a subset of downlink subframes of the reference TDD uplink and downlink configuration, all downlink subframes of the actual TDD uplink and downlink configuration may obtain uplink subframes for transmitting the HARQ-ACK of the PDSCH.

In an actual system, newer LTE version UEs and older UEs coexist. For the HARQ-ACK timing from the PDSCH to the PUCCH, the older UEs and the newer UEs may follow different TDD uplink and downlink configurations. For different TDD uplink and downlink configurations, when the HARQ-ACK of the downlink data is transmitted on the same one uplink subframe, there are different bundling windows, as illustrated in FIG. 2 .

Referring to FIG. 2 , letters “D” and “S” in subframes indicate downlinks subframes, and letter “U” indicates downlink subframes.

The newer UE transmits the HARQ-ACK of the PDSCH according to the HARQ-ACK timing of TDD uplink and downlink configuration 2, where the TDD uplink and downlink configuration used by the newer UE is the reference TDD uplink and downlink configuration indicated by the high-layer signaling or the physical layer signaling. The older UE uses the HARQ-ACK timing of TDD uplink and downlink configuration 0, where the TDD uplink and downlink configuration used by the older UE is a TDD uplink and downlink configuration indicated in system information (e.g., a System Information Block 1 (SIB1)) by a TDD UE that does not support adaptive traffic. When the newer UE and the older UE transmit the HARQ-ACK of PDSCH on the same uplink subframe 2 according to respective HARQ-ACK timings, the newer UE transmits the HARQ-ACK of downlink subframes 4, 5, 6, and 8, and the older UE transmits the HARQ-ACK of downlink subframe 6.

To transmit the HARQ-ACK of downlink subframes 4, 5, 6, and 8 corresponding to the newer UE, the downlink subframe 6 corresponding to the older UE has PUCCH format 1 a/1 b resources on the uplink subframe 2, and the downlink subframes 4, 5, and 8 have no PUCCH format 1 a/1 b resources on the uplink subframe 2. The PUCCH format 1 a/1 b resources are obtained according to the smallest Control Channel Element (CCE) index for scheduling the PDCCH.

For the newer UE, if PUCCH resources are reserved for each downlink subframe according to conventional technologies, because the number of downlink subframes in the reference TDD uplink and downlink configuration indicated by the high-layer signaling or the physical layer signaling is larger than the number of downlink subframes actually configured, not all of the PUCCH resources are actually needed, thereby wasting the PUCCH resources.

Accordingly, when the HARQ-ACK of the PDSCH in the traffic adaptive TDD system is transmitted, there is a problem how the newer UE is compatible with the older UE and a problem that the PUCCH resources are wasted in the prior art.

SUMMARY OF THE INVENTION

Accordingly, the present invention is designed to address at least the problems and/or disadvantages described above and to provide at least the advantages described below.

Accordingly, an aspect of the present invention is to provide a HARQ-ACK transmission method and apparatus in a traffic adaptive TDD system, which makes a newer UE compatible with an older UE, and addresses PUCCH resource waste.

In accordance with an aspect of the present invention, a method is provided for transmitting HARQ-ACK information by a UE in a TDD system. The method includes receiving, on a physical downlink control channel (PDCCH), downlink control information for scheduling a physical downlink shared channel (PDSCH), wherein the downlink control information includes a resource indicator indicating at least one physical uplink control channel (PUCCH) resource for transmitting the HARQ-ACK information and power control information for controlling transmission power of the UE; determining the transmission power of the UE based on the power control information; and transmitting the HARQ-ACK information based on the at least one PUCCH resource and the determined transmission power.

In accordance with another aspect of the present invention, a method is provided for receiving HARQ-ACK information by a BS in a TDD system. The method includes transmitting, to a UE, on a PDCCH, downlink control information for scheduling a PDSCH, wherein the downlink control information includes a resource indicator indicating at least one physical uplink control channel (PUCCH) resource for transmitting the HARQ-ACK information and power control information for controlling transmission power of the UE; and receiving, from the UE, the HARQ-ACK information which is transmitted by the UE based on the PUCCH resource indicated by the resource indicator and the transmission power determined based on the power control information.

In accordance with another aspect of the present invention, a UE is provided for use in a TDD system. The UE includes a transceiver; and at least one processor configured to receive, on a PDCCH, downlink control information for scheduling a PDSCH, wherein the downlink control information includes a resource indicator indicating at least one PUCCH resource for transmitting the HARQ-ACK information and power control information for controlling transmission power of the UE, determine the transmission power of the UE based on the power control information, and transmit the HARQ-ACK information based on the at least one PUCCH resource and the determined transmission power.

In accordance with another aspect of the present invention, a BS is provided for use in a TDD system. The BS includes a transceiver; and at least one processor configured to control the transceiver to transmit, to a UE, on a PDCCH, downlink control information for scheduling a PDSCH, wherein the downlink control information includes a resource indicator indicating at least one PUCCH resource for transmitting the HARQ-ACK information and power control information for controlling transmission power of the UE, and receive the HARQ-ACK information which is transmitted from the UE based on the PUCCH resource indicated by the resource indicator and the transmission power determined based on the power control information.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certain embodiments of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates a conventional frame structure in an LTE TDD system;

FIG. 2 is a schematic diagram illustrating problems in the conventional art;

FIG. 3 is a flowchart illustrating a HARQ-ACK transmission method in a traffic adaptive TDD system according to an embodiment of the present invention;

FIG. 4 illustrates a method for obtaining resources and a format used for HARQ-ACK transmission according to an embodiment of the present invention;

FIG. 5 illustrates a method for obtaining resources and a format used for HARQ-ACK transmission according to an embodiment of the present invention;

FIG. 6 illustrates a method for obtaining resources and a format used for HARQ-ACK transmission according to an embodiment of the present invention;

FIG. 7 illustrates a method for obtaining resources and a format used for HARQ-ACK transmission according to an embodiment of the present invention;

FIG. 8 illustrates a method for obtaining resources and a format used for HARQ-ACK transmission according to an embodiment of the present invention;

FIG. 9 illustrates a method for obtaining resources and a format used for HARQ-ACK transmission according to an embodiment of the present invention;

FIG. 10 illustrates a method for obtaining resources and a format used for HARQ-ACK transmission according to an embodiment of the present invention;

FIG. 11 illustrates a method for obtaining resources and a format used for HARQ-ACK transmission according to an embodiment of the present invention;

FIG. 12 illustrates a method for obtaining resources and a format used for HARQ-ACK transmission according to an embodiment of the present invention; and

FIG. 13 illustrates a user equipment according to an embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Various embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the following description, specific details such as detailed configuration and components are merely provided to assist the overall understanding of these embodiments of the present invention. Therefore, it should be apparent to those skilled in the art that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the present invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

The concept of PUCCH implicit resources is illustrated herein. In LTE Release8, for a PDSCH scheduled by a PDCCH on a downlink subframe, the HARQ-ACK of the PDSCH is transmitted on corresponding uplink subframes. The PUCCH format 1 a/1 b resources for transmitting the HARQ-ACK are obtained through scheduling the PDCCH of the PDSCH, i.e., the PUCCH format 1 a/1 b resources are obtained according to the lowest CCE index of the PDCCH. Herein, the PUCCH format 1 a/1 b resources obtained according to the lowest CCE index of the PDCCH are referred to as implicit resources.

FIG. 3 is a flowchart illustrating a HARQ-ACK transmission method in a traffic adaptive TDD system according to an embodiment of the present invention.

Referring to FIG. 3 , in step 301, a UE receives SIB1 and obtains a TDD uplink and downlink configuration to obtain the implicit resources of the PUCCH. The TDD uplink and downlink configuration is indicated in the current system information and does not support a dynamic traffic adaptive UE. That is, in step 301, the UE can obtain the implicit resources of the PUCCH according to the TDD uplink and downlink configuration that does not support the dynamic traffic adaptive UE.

In step 302, the UE obtains a HARQ-ACK timing that supports the dynamic traffic adaptive UE. For example, through receiving high-layer signaling, the UE may obtain the HARQ-ACK timing supporting the dynamic traffic adaptive UE.

In step 303, according to the HARQ-ACK timing, the UE transmits the HARQ-ACK using a specific PUCCH format on PUCCH resources determined according to a specific method.

Various methods of determining the PUCCH resources and PUCCH format used for the HARQ-ACK transmission in step 303 are described hereinbelow.

In accordance with an embodiment of the present invention, a Transmit Power Control (TPC) element in a PDCCH that schedules a PDSCH on all downlink subframes in a HARQ-ACK bundling window are all used as HARQ-ACK Resource Indicators (ARIs), which indicate PUCCH format 3 resources for transmitting the HARQ-ACK for the UE, the UE transmits the HARQ-ACK on the PUCCH format 3 resources indicated by the ARIs, and a power control command of PUCCH format 3/3A is used to implement the power control of the PUCCH transmitting the HARQ-ACK.

The TDD uplink and downlink configuration 1 is indicated by the current system information obtained by the UE from the SIB1 and does not support the dynamic traffic adaptive UE, the TDD uplink and downlink configuration 2 used by the HARQ-ACK timing is obtained by the UE through receiving the high-layer signaling and supports the dynamic traffic adaptive UE, and the TPC element in the PDCCH that schedules the PDSCH on downlink subframes 4, 5, 6, and 8 in the HARQ-ACK bundling window transmitting the HARQ-ACK on uplink subframe 2 are all used as ARIs, which indicates the PUCCH format 3 resources for transmitting the HARQ-ACK.

When the UE receives the PDCCH from at least one of the downlink subframes 4, 5, 6, and 8, the TPC element in the PDCCH are all used as the ARIs. That is, when the UE receives the PDCCH from at least one of the downlink subframes 4, 5, 6, and 8, the PUCCH format 3 resources indicated by the ARIs in the PDCCH are used to transmit the HARQ-ACK, as illustrated in FIG. 4 .

In accordance with another embodiment of the present invention, when a downlink subframe whose Downlink Assignment Index (DAI) is equal to 1 in the HARQ-ACK bundling window has implicit resources, the TPC element in the PDCCH on the downlink subframe is used as a TPC command, which is taken as a power control command of the PUCCH transmitting the HARQ-ACK. Besides, the TPC element in the PDCCH on other downlink subframes are used as the ARIs, which indicates the PUCCH format 3 resources for transmitting the HARQ-ACK. Further, when the UE only receives the PDCCH of downlink subframe whose DAI is equal to 1 and the downlink subframe has implicit resources, the UE transmits the HARQ-ACK on the implicit resources by using PUCCH format 1 a/1 b. If the downlink subframe has no implicit resources, the UE transmits the HARQ-ACK by using PUCCH format 3 on the PUCCH format 3 resources obtained according to the ARI in the PDCCH. When the UE receives the PDCCH of downlink subframe whose DAI is unequal to 1, the UE transmits the HARQ-ACK by using the PUCCH format 3 on the PUCCH format 3 resources obtained according to the ARI in the PDCCH.

The TDD uplink and downlink configuration 1 is indicated by the current system information obtained by the UE from the SIB1 and does not support the dynamic traffic adaptive UE, and the TDD uplink and downlink configuration 2 used by the HARQ-ACK timing is obtained by the UE through receiving the high-layer signaling and supports the dynamic traffic adaptive UE. If the PDCCH scheduling the PDSCH is detected only on the downlink subframe 5 and the DAI in the PDCCH is equal to 1, according to the TDD uplink and downlink configuration 1 that does not support the dynamical traffic adaptive UE, the downlink subframe 5 has implicit resources on the uplink subframe 2. The TPC element in the PDCCH on the downlink subframe 5 is used as a TPC command, and the HARQ-ACK is transmitted on the implicit resources of the downlink subframe 5 by using the PUCCH format 1 all b, as illustrated in FIG. 5 .

In accordance with another embodiment of the present invention, the UE obtains the PUCCH format 1 a/1 b resource corresponding to each bundling window through the high-layer signaling, the TPC element in the PDCCH on the downlink subframes whose DAI is unequal to 1 are used as the ARIs, which indicates the PUCCH format 3 resources for transmitting the HARQ-ACK. The TPC element in the PDCCH on the downlink subframes whose DAI is equal to 1 are used as a power control command of PUCCH transmitting the HARQ-ACK. Further, when the UE only receives the PDCCH of downlink subframe whose DAI is equal to 1, the UE transmits the HARQ-ACK by using the PUCCH format 1 a/1 b on the PUCCH format 1 a/1 b resources obtained according to the high-layer signaling, and when the UE receives the PDCCH of downlink subframe whose DAI is unequal to 1, the UE transmits the HARQ-ACK by using the PUCCH format 3 on the PUCCH format 3 resources obtained according to the ARIs in the PDCCH.

The TDD uplink and downlink configuration 1 is indicated by the current system information obtained by the UE from the SIB1 and does not support the dynamic traffic adaptive UE, and the TDD uplink and downlink configuration 2 is used by the HARQ-ACK timing that is obtained by the UE through receiving the high-layer signaling and supports the dynamic traffic adaptive UE. If the PDCCH scheduling the PDSCH is detected only on the downlink subframe 4 and the DAI in the PDCCH is equal to 1, according to the TDD uplink and downlink configuration 1 that does not support the dynamical traffic adaptive UE, the TPC element in the PDCCH on the downlink subframe 4 is used as a TPC command, and the HARQ-ACK is transmitted by using the PUCCH format 1 a/1 b on the PUCCH format 1 a/1 b resources obtained according to the high-layer signaling, as illustrated in FIG. 6 .

In accordance with another embodiment of the present invention, the UE obtains the PUCCH format 1 a/1 b resource corresponding to each bundling window through the high-layer signaling, the TPC element in the PDCCH on the downlink subframes whose DAI is unequal to 1 are used as the ARIs, which indicate the PUCCH format 3 resources for transmitting the HARQ-ACK, and the TPC element in the PDCCH on the downlink subframes whose DAI is equal to 1 are used as a power control command of the PUCCH transmitting the HARQ-ACK. Further, when the UE only receives the PDCCH of downlink subframe whose DAI is equal to 1, and the downlink subframe has implicit resources, the UE transmits the HARQ-ACK on the implicit resources by using the PUCCH format 1 a/1 b. If the downlink subframe has no implicit resources, the UE transmits the HARQ-ACK by using the PUCCH format 1 a/1 b on the PUCCH format 1 a/1 b resources obtained according to the high-layer signaling. When the UE receives the PDCCH of downlink subframe whose DAI is unequal to 1, the UE transmits the HARQ-ACK by using the PUCCH format 3 on the PUCCH format 3 resources obtained according to the ARIs in the PDCCH.

The TDD uplink and downlink configuration 1 is indicated by the current system information obtained by the UE from the SIB1 and does not support the dynamic traffic adaptive UE, and the TDD uplink and downlink configuration 2 is used by the HARQ-ACK timing that is obtained by the UE through receiving the high-layer signaling and supports the dynamic traffic adaptive UE.

If the PDCCH scheduling the PDSCH is detected only on the downlink subframe 5 and the DAI in the PDCCH is equal to 1, according to the TDD uplink and downlink configuration 1 that does not support the dynamical traffic adaptive UE, the downlink subframe 5 has implicit resources on the uplink subframe 2, the TPC element in the PDCCH on the downlink subframe 5 is used as a TPC command, and the HARQ-ACK is transmitted on the implicit resources of the downlink subframe 5 by using the PUCCH format 1 a/1 b, as illustrated in FIG. 7 .

If the PDCCH scheduling the PDSCH is detected only on the downlink subframe 4 and the DAI in the PDCCH is equal to 1, according to the TDD uplink and downlink configuration 1 that does not support the dynamical traffic adaptive UE, the downlink subframe 4 has no implicit resources on the uplink subframe 2, the TPC element in the PDCCH on the downlink subframe 4 is used as a TPC command, and the HARQ-ACK is transmitted by using the PUCCH format 1 a/1 b on the PUCCH format 1 a/1 b resources obtained according to the high-layer signaling, as illustrated in FIG. 8 .

In accordance with another embodiment of the present invention, the TPC element in the PDCCH on downlink subframes having implicit resources are used as a power control command of the PUCCH transmitting the HARQ-ACK, and the TPC element in the PDCCH on downlink subframes having no implicit resources are used as the ARIs, which indicate the PUCCH format 3 resources for transmitting the HARQ-ACK. Further, when the UE only receives the PDCCH having implicit resources, the UE transmits the HARQ-ACK on the implicit resources by using the PUCCH format 1 b or PUCCH format 1 a/1 b with a channel selection. When the UE receives the PDCCH having no implicit resources, the UE transmits the HARQ-ACK by using the PUCCH format 3 on the PUCCH format 3 resources obtained according to the ARIs in the PDCCH.

The TDD uplink and downlink configuration 1 is indicated by the current system information obtained by the UE from the SIB1 and does not support the dynamic traffic adaptive UE, and the TDD uplink and downlink configuration 2 is used by the HARQ-ACK timing that is obtained by the UE through receiving the high-layer signaling and supports the dynamic traffic adaptive UE.

If the PDCCH scheduling the PDSCH is detected on the downlink subframes 5 and 6, according to the TDD uplink and downlink configuration 1 that does not support the dynamic traffic adaptive UE, the downlink subframes 5 and 6 have implicit resources on the uplink subframe 2, the TPC element in the PDCCH on the downlink subframes 5 and 6 are used as a TPC command, and the HARQ-ACK is transmitted on the implicit resources of the downlink subframes 5 and 6 by using the PUCCH format 1 b with the channel selection, as illustrated in FIG. 9 .

In accordance with another embodiment of the present invention, the TPC element in the PDCCH on the downlink subframes having implicit resources are used as a power control command of the PUCCH transmitting the HARQ-ACK, and the TPC element in the PDCCH on the downlink subframes having no implicit resources are used as the ARIs, which indicates the PUCCH format 1 a/1 b resources for transmitting the HARQ-ACK. Further, the UE transmits the HARQ-ACK by using the PUCCH format 1 b with the channel selection on the implicit resources or the PUCCH format 1 a/1 b resources obtained according to the ARIs in the PDCCH.

The TDD uplink and downlink configuration 1 is indicated by the current system information obtained by the UE from the SIB1 and does not support the dynamic traffic adaptive UE, and the TDD uplink and downlink configuration 2 is used by the HARQ-ACK timing that is obtained by the UE through receiving the high-layer signaling and supports the dynamic traffic adaptive UE.

According to the TDD uplink and downlink configuration 1, which does not support the dynamic traffic adaptive UE, the downlink subframes 5 and 6 have implicit resources on the uplink subframe 2, and the TPC element in the PDCCH on the downlink subframes 5 and 6 are used as a TPC command. According to the TDD uplink and downlink configuration 1, which does not support the dynamical traffic adaptive UE, the downlink subframes 4 and 8 have no implicit resources on the uplink subframe 2, and the TPC element in the PDCCH on the downlink subframes 4 and 8 are used as the ARIs, which indicate the PUCCH format 1 a/1 b resources, as illustrated in FIG. 10 .

In accordance with another embodiment of the present invention, the TPC element in the PDCCH on all downlink subframes in the bundling window are used as a power control command of the PUCCH transmitting the HARQ-ACK, the UE obtains PUCCH format 1 a/1 b resources for each subframe having no PUCCH format 1 a/1 b resources according to the high-layer signaling, and the UE transmits the HARQ-ACK by using the PUCCH format 1 b with the channel selection on the implicit resources or the PUCCH format 1 a/1 b resources obtained according to the high-layer signaling.

The TDD uplink and downlink configuration 1 is indicated by the current system information obtained by the UE from the SIB1 and does not support the dynamic traffic adaptive UE, and the TDD uplink and downlink configuration 2 is used by the HARQ-ACK timing that is obtained by the UE through receiving the high-layer signaling and supports the dynamic traffic adaptive UE. The TPC element in the PDCCH on the downlink subframes 4, 5, 6, and 8 are used as a TPC command.

According to the TDD uplink and downlink configuration 1, which does not support the dynamic traffic adaptive UE, the downlink subframes 5 and 6 have implicit resources on the uplink subframe 2, the downlink subframes 4 and 8 have no implicit resources on the uplink subframe 2, and the UE obtains the PUCCH format 1 a/1 b resources of the subframes 4 and 8 according to the high-layer signaling, as illustrated in FIG. 11 .

In accordance with another embodiment of the present invention, the TPC element in the PDCCH on all downlink subframes in the bundling window are used as the ARIs, which indicates the PUCCH format 1 a/1 b resources for transmitting the HARQ-ACK, and a power control command of PDCCH format 3/3A is used to implement the power control of the PUCCH transmitting the HARQ-ACK. Further, the UE transmits the HARQ-ACK by using the PUCCH format 1 b with the channel selection on the PUCCH format 1 a/1 b resources obtained according to the ARIs in the PDCCH.

The TDD uplink and downlink configuration 1 is indicated by the current system information obtained by the UE from the SIB1 and does not support the dynamic traffic adaptive UE, and the TDD uplink and downlink configuration 2 is used by the HARQ-ACK timing that is obtained by the UE through receiving the high-layer signaling and supports the dynamic traffic adaptive UE. The TPC element in the PDCCH on the downlink subframes 4, 5, 6, and 8 are used as the ARIs, which indicates the PUCCH format 1 a/1 b resources. The UE transmits the HARQ-ACK by using the PUCCH format 1 b with the channel selection on the PUCCH format 1 a/1 b resources obtained according to the ARIs in the PDCCH, and the power control command of PUCCH format 3/3A is used to implement the power control of the PUCCH transmitting the HARQ-ACK, as illustrated in FIG. 12 .

In accordance with another embodiment of the present invention, the UE obtains the PUCCH format 3 resource corresponding to each bundling window through the high-layer signaling, and the TPC element in the PDCCH on all downlink subframes within each bundling window are used as a power control command of the PUCCH transmitting the HARQ-ACK. Further, when the UE only receives the PDCCH of downlink subframe whose DAI is equal to 1, and the downlink subframe has implicit resources, the UE transmits the HARQ-ACK on the implicit resources by using the PUCCH format 1 a/1 b. If the downlink subframe has no implicit resources, the UE transmits the HARQ-ACK by using the PUCCH format 3 on the PUCCH format 3 resources obtained according to the high-layer signaling. When the UE receives the PDCCH of downlink subframe whose DAI is unequal to 1, the UE transmits the HARQ-ACK by using the PUCCH format 3 on the PUCCH format 3 resources obtained according to the ARIs in the PDCCH.

In accordance with another embodiment of the present invention, the UE obtains the PUCCH format 3 resource corresponding to each bundling window through the high-layer signaling, and the TPC element in the PDCCH on the downlink subframes whose DAI is unequal to 1 are used as a power control command of the PUCCH transmitting the HARQ-ACK. Further, when the UE only receives the PDCCH of downlink subframe whose DAI is equal to 1, and the downlink subframe has implicit resources, the UE transmits the HARQ-ACK on the implicit resources by using the PUCCH format 1 a/1 b. If the downlink subframe has no implicit resources, the UE transmits the HARQ-ACK by using the PUCCH format 3 on the PUCCH format 3 resources obtained according to the high-layer signaling. When the UE receives the PDCCH of downlink subframe whose DAI is unequal to 1, the UE transmits the HARQ-ACK by using the PUCCH format 3 on the PUCCH format 3 resources obtained according to the ARIs in the PDCCH.

FIG. 13 illustrates a UE according to an embodiment of the present invention.

Referring to FIG. 13 , the UE 1300 includes a transmitter 1310, a receiver 1320, and a controller 1330. The transmitter 1310 and the receiver 1320, respectively, include transmission circuitry and reception circuitry for communicating with a network entity such as a base station, under the control of the controller 1330.

The controller 1330 controls reception of HARQ-ACK feedback information by the receiver 1320, and transmission of the HARQ-ACK by the transmitter 1310.

Similarly, a base station may include a transmitter, a receiver, and a controller, and performing a reverse operation of the UE. Specifically, the controller generates the SIB according TDD uplink and downlink configuration, and controls HARQ-ACK timing. The transmitter of the base station transmits the SIB to the UE and the receiver receives HARQ-ACK from the UE.

As can be seen from the above described embodiments, a HARQ-ACK transmission method and apparatus in a traffic adaptive TDD system provide the PUCCH resource mapping methods and the methods of determining the PUCCH format used for HARQ-ACK transmission, thereby dynamically adjusting the assigned PUCCH resources according to actual uplink and downlink configuration when the uplink and downlink configuration changes dynamically. Further, the existing PUCCH resources can be fully utilized, thereby effectively saving the physical resources of uplink subframes.

While the present invention has been particularly shown and described with reference to certain embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims and their equivalents. 

What is claimed is:
 1. A method for transmitting hybrid automatic repeat request-acknowledgement (HARQ-ACK) information by a user equipment (UE) in a time division duplexing (TDD) system, the method comprising: receiving, on a physical downlink control channel (PDCCH), downlink control information for scheduling a physical downlink shared channel (PDSCH), wherein the downlink control information includes a resource indicator indicating at least one physical uplink control channel (PUCCH) resource for transmitting the HARQ-ACK information and power control information for controlling transmission power of the UE; determining the transmission power of the UE based on the power control information; and transmitting the HARQ-ACK information based on the at least one PUCCH resource and the determined transmission power.
 2. The method of claim 1, wherein the downlink control information is received on at least one downlink subframe having implicit PUCCH resources and at least one downlink subframe having no implicit PUCCH resources.
 3. The method of claim 1, wherein the resource indicator is included in all downlink control information scheduling the PDSCH.
 4. The method of claim 1, wherein the HARQ-ACK information is transmitted using one of a PUCCH format 3 or a PUCCH format 1 a/1 b.
 5. A method for receiving hybrid automatic repeat request-acknowledgement (HARQ-ACK) information by a base station (BS) in a time division duplexing (TDD) system, the method comprising: transmitting, to a user equipment (UE), on a physical downlink control channel (PDCCH), downlink control information for scheduling a physical downlink shared channel (PDSCH), wherein the downlink control information includes a resource indicator indicating at least one physical uplink control channel (PUCCH) resource for transmitting the HARQ-ACK information and power control information for controlling transmission power of the UE; and receiving, from the UE, the HARQ-ACK information which is transmitted by the UE based on the PUCCH resource indicated by the resource indicator and the transmission power determined based on the power control information.
 6. The method of claim 5, wherein the downlink control information is received on at least one downlink subframe having implicit PUCCH resources and at least one downlink subframe having no implicit PUCCH resources.
 7. The method of claim 5, wherein the resource indicator is included in all downlink control information scheduling the PDSCH.
 8. The method of claim 5, wherein the HARQ-ACK information is received using one of a PUCCH format 3 or a PUCCH format 1 b.
 9. A user equipment (UE) in a time division duplexing (TDD) system, the UE comprising: a transceiver; and at least one processor coupled to the transceiver, wherein the at least one processor is configured to: receive, on a physical downlink control channel (PDCCH), downlink control information for scheduling a physical downlink shared channel (PDSCH), wherein the downlink control information includes a resource indicator indicating at least one physical uplink control channel (PUCCH) resource for transmitting the HARQ-ACK information and power control information for controlling transmission power of the UE, determine the transmission power of the UE based on the power control information, and transmit the HARQ-ACK information based on the at least one PUCCH resource and the determined transmission power.
 10. The UE of claim 9, wherein the at least one processor is further configured to receive the downlink control information on at least one downlink subframe having implicit PUCCH resources and at least one downlink subframe having no implicit PUCCH resources.
 11. The UE of claim 9, wherein the resource indicator is included in all downlink control information scheduling the PDSCH.
 12. The UE of claim 9, wherein the HARQ-ACK information is transmitted using one of a PUCCH format 3 or a PUCCH format 1 a/1 b.
 13. A base station (BS) in a time division duplexing (TDD) system, the BS comprising: a transceiver; and at least one processor configured to: transmit, to a user equipment (UE), on a physical downlink control channel (PDCCH), downlink control information for scheduling a physical downlink shared channel (PDSCH), wherein the downlink control information includes a resource indicator indicating at least one physical uplink control channel (PUCCH) resource for transmitting the HARQ-ACK information and power control information for controlling transmission power of the UE, and receive the HARQ-ACK information which is transmitted from the UE based on the PUCCH resource indicated by the resource indicator and the transmission power determined based on the power control information.
 14. The BS of claim 13, wherein the at least one processor is further configured to transmit the downlink control information on at least one downlink subframe having implicit PUCCH resources and at least one downlink subframe having no implicit PUCCH resources.
 15. The BS of claim 13, wherein the resource indicator is included in all downlink control information scheduling the PDSCH.
 16. The BS of claim 13, wherein the HARQ-ACK information is received using one of a PUCCH format 3 or a PUCCH format 1 a/1 b. 